The principal objective of the proposed research is to define the mechanisms involved in the regulation of the composition, rate of synthesis and secretion of mucin glycoproteins in respiratory tissues. This process will be examined in structural studies and in studies of individual enzymes and particulate multienzyme systems. Mucin glycoproteins produced by swine trachea maintained in organ culture will be isolated and the structure of their oligosaccharide chains will be determined by periodate oxidation, hydrolysis with specific glycosidases and examination by gas chromatography. Individual sugar residues will be sequentially removed from the glycoprotein with highly purified glycosidases to prepare glycosyl acceptors which will be used in biosynthetic studies with cell-free preparations isolated from trachea mucosa. The trachea organ culture will also be used to examine the regulation of mucin biosynthesis under conditions mimicking hypersecretion. The influence of various irritants on the rate of synthesis and composition of the oligosaccharide component of mucin glycoproteins will be examined with this tracheal explant system. The study of these processes with both an in vivo and in vitro approach may result in the development of a pertinent model system to investigate the mechanisms involved in the regulation of the biosynthesis and secretion of mucin glycoproteins in this tissue.